Just remind yourself that they've looked at your CV (or resumé if you're american ; ) and got you in for an interview rather than shredding it. This means that they like the look of you .. you have the skills to do the job. They just want to make sure you're okay as a person. Also remember that it's not just them working out if they want you to work for them.. it's also you working out if you want to work for them. It's great when you end up grilling the interviewer about the company. Shows you have a proper interest in the company and the work you'll be doing. Also .. assume you have the job. Say things like "How much holiday will I get" rather than "How much holiday would I get" .. sounds more positive .. sounds as though you know you're going to get the job, but not in an arrogant way.
But at the end of the day .. I feel your pain .. I can get a little nervous, although not half as much as I used to. The last one I went to I actually intimidated the interviewer lol. I don't think he had any braincells anyway =)
Just relax and be yourself and if that fails, bribe the bastards ; )
